1. Field of the Invention
The present invention relates to an adhesive tape and products made therefrom. More particularly, the present invention relates to a three-layer moisture barrier adhesive tape useful in a wide variety of applications.
2. Description of the Prior Art
Decorative laminates prepared by heat and pressure consolidation have been produced commercially for a number of years, and have found widespread acceptance in the building and furniture industry as counter and table tops, bathroom and kitchen work surfaces, wall paneling, partitions and doors. Such decorative laminates can be described as containing a number of laminae consolidated to form a unitary structure carrying a surface decoration which can range from something as simple as a solid color to something as complex as an embossed simulated wood grain finish.
In many instances, decorative laminates are bonded to a reinforcing substrate, such as plywood, hardboard, fiber board, particle board or the like. Adhesives such as contact adhesives, urea-formaldehyde, white glues (polyvinyl acetate emulsions), hot melts, phenolic or resorcinol-formaldehyde epoxy, coal tar, animal glues, and the like are commonly used to secure decorative laminates to a reinforcing substrate. The adhesives vary in their cost and reliability.
While the adhesives previously used within the industry have proven to be somewhat reliable, the prior adhesives feature many limitations. For example, the size of some decorative laminate countertops often necessitates the placement of two adjacent pieces of decorative laminate upon the substrate. As such, a seam must be included on the countertop.
As those skilled in the art will readily appreciate, a seam in a countertop represents the weak point of the entire countertop. Specifically, seams are susceptible to water penetration, resulting in swelling of the substrate and subsequent delamination of the laminate. In addition, water penetration weakens the adhesive adjacent to the seam, allowing the decorative laminate to deflect upwardly in an unsightly manner.
Decorative laminates are manufactured within a certain thickness tolerance. The tolerance results in thickness variations making it very difficult to align the decorative surfaces at a seam. As a result, adjacent laminates along a seam are generally not perfectly coplanar. Any difference in thickness along a seam creates an undesirable ridge and prevents a countertop, for example, from creating the appearance of a continuous, integral surface.
Laminate seams are subject to spreading and contracting over time due to environmental conditions. Specifically, exposure to varying heat and/or moisture conditions may cause a substrate and/or laminate to expand or contract. Since the seam represents a weak point in the countertop, expansion or contraction of the substrate and/or laminate results in movement of the seam in an undesirable manner.
The problems associated with the expansion and contraction of decorative laminate products manifests itself at the corner of laminated articles where the layers of the decorative laminate overlap each other along the edge seam. Delamination or movement caused by environmental conditions causes the laminate to loosen and become subject to damage or breakage. The edge of the decorative laminate at the corner may expand and protrude beyond the corner. The exposed edge is subject to being caught by anything that rubs up against it and, thereby, being easily broken or damaged. Examples of this are broken laminates on the corners of restaurant table edges, cabinet door or drawer corners, desk corners etc.
Additionally, adhesives commonly employed are very messy and present many problems in both the large scale production of decorative laminate products and the small scale production of decorative laminate products. Specifically, adhesives used in the large scale production of decorative laminate products present a continual problem with the machinery used during the production process. A battle must be continually fought to keep the adhesive from transferring onto, and contaminating, equipment.
Traditional adhesives also present problems when decorative laminate products are produced on a smaller scale. For example, where a decorative countertop is assembled within a consumer's home, the craftsman must be continually aware of potential damage that can be caused by spilled adhesive.
The common use of adhesive also presents problems where a layer of adhesive is used between a substrate and a thin piece of decorative laminate. Specifically, imperfections or flaws in the surface finish of the substrate can telegraph through the decorative laminate, adversely affecting the manufactured finish of the decorative laminate.
Telegraphing is also a problem where decorative laminates are wrapped about a piece of molding substrate, or other tooled substrate, to create laminated molding. Since the molding substrate is commonly machined with rotary knife blades, unevenness is created in the resulting molding substrate surface. This unevenness telegraphs through the decorative laminate after it is bonded to the substrate. Special backers have been positioned between the substrate and the decorative laminate to minimize the telegraphing. The need for such backers increases manufacturing costs due to the additional time and materials needed.
Based upon the foregoing, a need exists for an improved bonding technique, as well as products manufactured in accordance with the improved bonding technique. The present invention provides an improved adhesive tape which may be readily employed to overcome the shortcoming of prior art techniques and to solve the problems discussed above.